Add JSON-LD Context Document for Data Package (#874)

* Add JSON-LD Context Document for Data Package

* Update schemas/context/README.md

Co-authored-by: Dan Feder <[email protected]>

---------

Co-authored-by: Dan Feder <[email protected]>

package.json

@@ -27,6 +27,7 @@
     "glob": "^7.1.1",
     "js-yaml": "^3.13.1",
     "json-schema-ref-parser": "^9.0.9",
+    "jsonld": "^8.3.2",
     "markdown-it-footnote": "",
     "mermaid": "^9.1.2",
     "mocha": "^9.2.2",

schemas/context/README.md

@@ -0,0 +1,11 @@
+This directory contains non-normative JSON-LD Context Documents to convert Data Package Formats to RDF. 
+
+Right now, it only contains a context for Data Package documents.
+Properties `resources`, `profile`, and contributor roles are ignored.
+
+Note that the use of POSIX paths will reduce the ability for RDF conversion. In particular:
+
+- property `id`, if given, MUST be a URI
+- property `image` with POSIX path will be ignore
+- elements with property `path` having a POSIX path value be ignored
+

schemas/context/data-package.json

@@ -0,0 +1,45 @@
+{
+  "dcat": "http://www.w3.org/ns/dcat#",
+  "dct": "http://purl.org/dc/terms/",
+  "foaf": "http://xmlns.com/foaf/0.1/",
+  "schema": "https://schema.org/",
+  "prov": "http://www.w3.org/ns/prov#",
+  "name": "dct:identifier",
+  "id": "@id",
+  "licenses": {
+    "@id": "dct:license",
+    "@context":{
+      "name": "dct:identifier",
+      "title": "dct:title",
+      "path": "@id"
+    }
+  },
+  "title": "dct:title",
+  "description": "dct:description",
+  "homepage": {
+    "@id": "foaf:homepage",
+    "@type": "@id"
+  },
+  "version": "dct:version",
+  "sources": {
+    "@id": "prov:wasDerivedFrom",
+    "@context": {
+      "path": "@id",
+      "title": "foaf:name",
+      "email": "foaf:mbox"
+    }
+  },
+  "contributors": {
+    "@id": "dct:contributor",
+    "@context": {
+      "title": "foaf:name",
+      "organization": "schema:affiliation",
+      "email": "foaf:mbox"
+    }
+  },
+  "keywords": "dcat:keyword",
+  "image": {
+    "@id": "foaf:img"
+  },
+  "created": "dct:created"
+}

test/files/data-package-1.json

@@ -0,0 +1,33 @@
+{
+  "name": "name-of-package",
+  "id": "https://example.org/id/1234",
+  "licenses": [{
+    "name": "ODC-PDDL-1.0",
+    "path": "http://opendatacommons.org/licenses/pddl/",
+    "title": "Open Data Commons Public Domain Dedication and License v1.0"
+  }],
+  "title": "A nice title",
+  "description": "whatever...",
+  "homepage": "http://example.org",
+  "version": "1.2.3",
+  "sources": [{
+    "title": "Sample Source",
+    "path": "http://example.org/source",
+    "email": "[email protected]",
+    "version": "0.0.1"
+  }],
+  "contributors": [{
+    "title": "Ex Ample",
+    "email": "[email protected]",
+    "path": "http://example.org/staff/ex",
+    "organization": "Acme",
+    "role": "author"
+  }],
+  "keywords": [ "example", "stuff" ],
+  "image": "http://example.org/image.png",
+  "created": "1985-04-12T23:20:50.52Z",
+  "resources": [{
+    "name": "resource-name",
+    "path": "http://example.org/resource-path.csv"
+  }]
+}

test/files/data-package-1.nt

@@ -0,0 +1,20 @@
+<http://example.org/source> <http://purl.org/dc/terms/version> "0.0.1" .
+<http://example.org/source> <http://xmlns.com/foaf/0.1/mbox> "[email protected]" .
+<http://example.org/source> <http://xmlns.com/foaf/0.1/name> "Sample Source" .
+<http://opendatacommons.org/licenses/pddl/> <http://purl.org/dc/terms/identifier> "ODC-PDDL-1.0" .
+<http://opendatacommons.org/licenses/pddl/> <http://purl.org/dc/terms/title> "Open Data Commons Public Domain Dedication and License v1.0" .
+<https://example.org/id/1234> <http://purl.org/dc/terms/contributor> _:b0 .
+<https://example.org/id/1234> <http://purl.org/dc/terms/created> "1985-04-12T23:20:50.52Z" .
+<https://example.org/id/1234> <http://purl.org/dc/terms/description> "whatever..." .
+<https://example.org/id/1234> <http://purl.org/dc/terms/identifier> "name-of-package" .
+<https://example.org/id/1234> <http://purl.org/dc/terms/license> <http://opendatacommons.org/licenses/pddl/> .
+<https://example.org/id/1234> <http://purl.org/dc/terms/title> "A nice title" .
+<https://example.org/id/1234> <http://purl.org/dc/terms/version> "1.2.3" .
+<https://example.org/id/1234> <http://www.w3.org/ns/dcat#keyword> "example" .
+<https://example.org/id/1234> <http://www.w3.org/ns/dcat#keyword> "stuff" .
+<https://example.org/id/1234> <http://www.w3.org/ns/prov#wasDerivedFrom> <http://example.org/source> .
+<https://example.org/id/1234> <http://xmlns.com/foaf/0.1/homepage> <http://example.org> .
+<https://example.org/id/1234> <http://xmlns.com/foaf/0.1/img> "http://example.org/image.png" .
+_:b0 <http://xmlns.com/foaf/0.1/mbox> "[email protected]" .
+_:b0 <http://xmlns.com/foaf/0.1/name> "Ex Ample" .
+_:b0 <https://schema.org/affiliation> "Acme" .

test/rdf.js

@@ -0,0 +1,19 @@
+const util = require('util')
+const readFile = util.promisify(require('fs').readFile)
+const {assert} = require('chai')
+const jsonld = require('jsonld')
+
+const toRDF = async file => {
+  const doc = require(file)
+  doc["@context"] = require("../schemas/context/data-package.json")
+  const triples = await jsonld.toRDF(doc, {format: 'application/n-quads'})
+  return triples.split("\n").sort().filter(Boolean).join("\n")+"\n"
+}
+
+describe('rdf', () => {
+  it('data-package', async () => {
+    const rdf = await toRDF('./files/data-package-1.json')
+    const nt = await readFile('test/files/data-package-1.nt', 'utf-8')
+    assert.equal(rdf, nt)
+  })
+})